Boiler-furnace.



Patented Nov. 17, 1908.

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OLIVER B. DAWSON, OF CALDWELL, NEW JERSEY.

BOILE lit-FURNACE Specification of Letters Patent.

Patented Nov. 1'7, 1908.

Application filed. October 16, 1907. Serial No. 397,680.

To all whom it may concern:

Be it known that I, OLIVER l3. DAWSON, of Caldwell, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Boiler-Furnaces; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The object of my invention is to provide improved, simple and highly efiicient means for insuring complete and thorough combustion of the soot, hydro-carbon and carbon monoxid gases in steam boiler furnaces at the point and instant of distillation-in the fire-box.

The invention will be hereinafter fully set forth and particularly pointed out in the claim.

In the accompanying drawing, the figure is a vertical longitudinal sectional view of a return tubular boiler furnace equipped with my improvement.

Referring to the drawings, 1 represents a return tubular boiler mounted in a brick settino 2; 3 the fire-box; and at the combustion chamber, all of these parts being of the usual or any preferred construction and relative arrangement.

5 designates an air pipe or flue which passes down along the rear wall of the boiler setting and within the uptake 6 where it is coiled as at 7, and terminates in branches 8 and 9 communicating with two of the tubes 10 and 12 of the boiler. At the opposite or front end of the boiler these tubes open into branches 18, 14, forming one terminal of a second or complementary coil 15, constitut ing a superheater, arranged beneath the smoke stack and in the line of travel of the products of combustion thereto. The coil 15 dischar es into the fire-box at a point above the re-bed and supplies a current of air heated to the degree necessary to produce high temperature combustion, thus insuring a complete combustion of what might otherwise pass off unconsumed, all soot, hydrocarbon, and carbon-monoxid gas being entirely oxidized.

Although I have specified the pipe 5 as communicating with two of the boiler tubes, and the use of these tubes as a means for conducting the air to the front of the furnace, yet I may carry the pipe 5 directly through these tubes if necessary.

In practice I have found that the pull or suction of the stack is suflicient to create and maintain the current of air through the coils, yet the draft may be forced by a blower if desired.

To those skilled in this art it is known that in order to effect complete combustion of the soot, hydrocarbon and carbon-monoxid gases arising from a coal fire in a steam boiler furnace air must be fed to the unburned products of combustion at the moment of their distillation. Experience has shown that the best results follow from introducing highly heated air directly into the unburned products above the fuel-bed. The air must be heated to a degree of at least 850 F. to cause quick and intense combustion within the fire-box. But the majority of improvements along these lines involve expensive additions to the existing types of boilers and furnaces, and where the various means for heating the air have contemplated passing it through pipes seated in the bridge wall or other parts of the masonry setting it has been found that the heat of the burning fuel tended to melt the unprotected metal parts. By my invention no change or alteration whatever is necessary in the boiler or furnace in order to admit of using my improved means for supplying hot air; that such means may be installed at a minimum expense; that the air pipes are not at any point subjected to heat so great as to occasion their melting; and that the discharge of the heated air upon the tire bed insures thorough mingling with the unburned products of combustion.

I claim as my invention:

The combination with a steam boiler furnace having a fire-box, an up-take at the rear end, boiler tubes open at their rear ends to said up-take, and a smoke-stack at the front of the furnace, of means for introducing highly-heated atmospheric air to said fire-box comprising a pipe open at one end to the atmosphere and extending into said up-take and coiled therein and communicating with one or more of said boiler tubes at their rear ends, and a second pipe leading from such boiler tubes at their front ends to said fire-box, said second pipe being coiled In testimony whereof, I have signed this and located beneath said smoke-stack and specificatlon 1n the presence OfUVOSHbSCI'lbhaving its dlscharge end openlng into the ing Witnesses.

fire-box at or near the fire-bed, said pipes 7 OLIVER B. DAWSON. 5 andcoils being so located as not to be eX WVitnesses:

posed Within the fire box to the direct action JOHN A. MURPHY,

of the heat generated by the furnace. FRANCIS S. MAGINIS. 

